Whilst I had the rear clam off the Esthi, I thought I would address some of the ‘heat’ issues. Amongst other things I rewrapped the exhaust box and part of the outlet pipes with heatwrap. The stuff looks like old sacking but is remarkably effective. Took the car out for a 20 mile sprint and on return could place my hand on the box without discomfort. Highly recommended.
[image]SELOC | Lotus Enthusiasts Club
…on return could place my hand on the box without discomfort…
That could have gone wrong!
…on return could place my hand on the box without discomfort…
That could have gone wrong!
Reminds me of my viz where one of characters tries something and it doesn’t work … only to end with the immortal line…
“my, how we laughed on the way to casualty”
I would advise against wrapping the Cat bodies. You’re in danger of melting the matrix on them.
Most matrices are ceramic, which has a higher melting point than most metals!
True but if the elements of the matrix are very thin then surely metal would out last them?
Ian
I’ve melted the ceramic matrix in a Nissan’s CAT (street car), so I can vouch they do melt!
Steel melts at about 1200 Celsius (regardless how thick) and creamics can endure upto 3000 Celsius. Best illustrated by ceramic crucibles that carry molten steel, furnace lining etc. Most ceramics don’t melt at all!
Most heat in the Cat steel casing would be conducted along the exhaust pipe.
Yes, but maybe there are different varieties or qualities of ceramic?
I tell you, I had to grind the stuff out of there (drill + round mill), it was plugging the exhaust, and wasn’t metal.
It happened to me, that’s all I can say.
Steel melts at about 1200 Celsius (regardless how thick) and creamics can endure upto 3000 Celsius. Best illustrated by ceramic crucibles that carry molten steel, furnace lining etc. Most ceramics don’t melt at all!
Most heat in the Cat steel casing would be conducted along the exhaust pipe.
The ceramic used in the substrate is only there to hold the coating of precious metals which act as the catalyser. It’s these metals which will melt - regardless of the substrate.
Steel melts at about 1200 Celsius (regardless how thick) and creamics can endure upto 3000 Celsius. Best illustrated by ceramic crucibles that carry molten steel, furnace lining etc. Most ceramics don’t melt at all!
Most heat in the Cat steel casing would be conducted along the exhaust pipe.The ceramic used in the substrate is only there to hold the coating of precious metals which act as the catalyser. It’s these metals which will melt - regardless of the substrate.
The most common metals in catalysts are:
Platinum with a melting point of 1768 Celsius,
Palladium with a melting point of 1554 Celsius,
Rhodium with a melting point of 1964 Celsius.
Steel melts at about 1200 Celsius.
The ceramic used in the substrate is only there to hold the coating of precious metals which act as the catalyser. It’s these metals which will melt - regardless of the substrate.
The most common metals in catalysts are:
Platinum with a melting point of 1768 Celsius,
Palladium with a melting point of 1554 Celsius,
Rhodium with a melting point of 1964 Celsius.
Steel melts at about 1200 Celsius. [/quote]
No-one is trying to re-write the laws of physics Ken. Catalyst failure through heat degradation of the substrate is very common. I notice you have no sensors after the Cats, so if they do overheat there’ll be no warning. The metals you list above are applied in a wash-coat, microns thick. This will easily overheat/fail long before the casing/pipework reaches their critical temperature. Wrapping the Cats is merely shortening the odds - why take the chance?
my engineering science knowledge is limited at best, but i recall that many alloys often exhibit much lower melting points than their elemental constituents anyway don’t they? eutectic curves ring a bell for anyone else??
marvellous ang… another blast from the past…
this googled link explains it quite well for anyone that CBA… Eutectic Phase Diagram
i never cease to amaze myself!